Such assembly is common in numerous technical fields, regardless of the structure and/or the composition of the materials and/or the final purpose of the elements.
Such assemblies are desirable in numerous technical fields such as building and public works, furniture, and mechanical engineering, in particular.
For greater simplicity, the invention is described in the field of glazing. The scope of the invention is not limited in any way to glazing, which is merely the context in which the invention originated.
Likewise, the term "envelope element" for designating the elements that are hard and brittle is employed herein for the purpose of simplicity. It implies no limitation as to the number and/or disposition of such elements.
A technical problem solved by the invention is described with reference to an example concerning laminated glazing.
The following documents are mentioned in this field.
Document DE-A-38 37 701 describes a window provided with holes into which adhesive is inserted for bonding purposes.
Document GB-A-2 024 297 describes a window with a channel section rail onto which fixing bolts are welded.
Document US-A-4 307 551 describes glass plates for covering a wall, and including section member rails stuck in the region of the edges.
Document EP-A-344 486 describes a thick glass plate for covering purposes, with sheet metal stuck thereto.
In laminated glazing, the envelope elements are generally made of glass, synthetic material, or the like. The deformable element(s) is/are generally made of thermoplastic synthetic material in the form of laminations.
The elements are said to be "deformable" since they are suitable for being deformed plastically and irreversibly, commonly known as "creep".
A rise in temperature, e.g. under the effect of the sun, increases creep.
In particular, under certain conditions of temperature and/or stress, these elements are deformed because of their low resilience. Thus, they do not return to their original shape once the conditions have gone.
For example, the application of stress on laminated glazing, e.g. in the form of compression for holding the glazing in position, often gives rise to creep.
This causes mechanical damage, and spoils the waterproofing of the glazing and/or the unit in which it is integrated.
The mechanical damage appears as a change in the shape of the glazing (delamination, thickness, etc.).
When that happens, the glazing is no longer properly held or driven. In particular, the connection between the glazing and the holding and/or drive means is degraded (backlash, vibration, jamming, etc.), and may even be broken.
At present, industrial solutions are unsatisfactory, in particular because of cost.
To secure the glazing to its holding and/or drive means, it is common practice to provide it with discontinuities that open out to two opposite faces in the main direction of the stresses. These discontinuities are generally ports, holes, or openings.
This weakens the glazing and increases its cost. Also, the means secured to the glazing are then heavy, whereas, on the contrary, industry is looking for ways of reducing weight.
The same drawback of weight is to be found with means secured by clamping the glazing by means of a yoke.
A channel section insert, e.g. made of rubber or the like, generally engages the edge of the glazing and is rigidly connected to the yoke. The size, the reliability, and the simplicity of the unit including the glazing all suffer therefrom.
These drawbacks present further difficulties when faced with increasing requirements of the industry concerning soundproofing, reduction in weight and size, and concerning safety and reliability (ability of the assembly to withstand shock and conditions of heat or humidity, etc.).
It is also appropriate to restrict or even eliminate manufacturing rejects due to delamination, defects, or breakage, e.g. due to final assembly in an autoclave (often at 1.2 MPa and at 145.degree. C. for more than 1 hour).
Delamination can also occur during assembly or during the aging cycle, and can escape attention during assembly, which is one of the causes of such delamination.
The above problems are described in the context of laminated glazing, but they also occur in numerous other technical fields.
There is a common need to apply compression stresses from the outside on a device having an envelope which is hard and brittle and a core which is flexible. A term sometimes used is "low resilience".
This applies to a panel or part provided with hard outer layers (cellulose material, synthetic material, metal, or porcelain or plaster) against which stresses need to be applied, and an internal part that is deformable, such as insulating foam, a sealing film, a biological barrier, or the like.
Such panels or parts are often to be found in furniture, public works, building, mechanical engineering, etc.